A pyridazinone compound represented by the following formula:
whereinR1 is a substituent,R2 is a hydrogen atom or a substituent,R3 is a hydrogen atom or a substituent,Ring A is an aromatic ring which can be substituted, andRing B is a 5-membered heteroaromatic ring which can be substituted,is known to have a high safety and a superiorphosphodiesterase 10A inhibitory activity, which is useful as an agent for the prophylaxis or treatment of schizophrenia and the like (Patent Document 1).
As a production method of a pyridazinone compound, methods disclosed in Patent Documents 1 to 6 and non-Patent Documents 1 to 5 are known.
There is a demand for the provision of an advantageous method of producing a pyridazinone compound, which is suitable for industrial production.